Fibrous container manufacture



Dec. 1, 1942. R. P. BIGGER FIBROUS CONTAINER MANUFACTURE Filed March 8,1941 INVENT OR.

BY v i -wc0 I ATTORNEYS Patented Dec. 1 1942 FIBROUS CONTAINERMANUFACTURE Richard P. Bigger, Lombard, 111., assignor to American CanCompany, New York, N. Y., a corporation of New Jersey Application.-March 8, 1941, Serial No. 382,461

4 Claims.

in preparing the fibre end so that such wall will prevent penetration ofthe product through the wall structure. Obviously, in the case ofmetalends which are impervious to oil seepage no special treatment ofthe end stock willbe necessary. However, the seams in such a containerare far more difiicult to make tight and the end seams between the bodyand its bottom and top ends are particularly vulnerable.

The present invention is particularly directed to overcoming leaky seamdifiiculties and contemplates a procedure by which such .seams or jointsare made fully secure so that oil and greasy contents sealed into thecan are prevented from passing through the seam by seepage or otherwise.It follows that containers otherwise adaptable to contents of thisnature and which embody end seams which. are tight enough to resist anyoil seepage and otherwise properly made as in the present method stepsmake the containers satisfactory for holding difiicult materials such aslard or vegetable and mineral oils, etc.

An object of the present invention is the provision of a method ofproviding in fibre containers end seam joints between can bodies and canends which are impermeable to the passage of oily or greasy productssealed in the containers.

Another object is the provision of a method of forming oil and greaseproof joints between fibre can bodies and metal ends so that thecontainer will hold lard or vegetable and mineral oils and like productswithout danger of leaking.

Numerous other objects and advantages of the invention will be apparentas it is better understood from the following description, which, takenin connection with the accompanying drawing, discloses a preferredembodiment thereof.

Referring to the drawing:

Figure 1 is a perspective view of a fibre can body which has beentreated to make the body wall impervious to the seepage of oily andgreasy products, such a body being subjected to method steps embodied inthe present invention;

member which constitutes a part of a. container made with such a body;

Fig. 3 is a schematic sectional view of apparatus for applying a sealingmixture to the inside surface adjacent an end of the can body of thetype shown in Fig. 1 and illustrating the application of such sealingmaterial by rotation of a roller in a bath containing the sealingmaterial;

Fig. 4 is a schematic view in section illustrating an assembled fibrecan body and a metal end or bottom member and showing a seaming rollerfor crimping the flange of the can end onto the fibre body;

Fig. 5 is a schematic view in section of a heating element for heatingthe seam joint of a container after the body and end members have beensecured together; and

Fig. 6 is an enlarged sectional view of the lower corner of a fibrecontainer and metal end embodying an end seam or joint and illustratingthe results of the final steps in the presentmethod.

A suitable fibre container body ll (Fig. 1) may be formed in aconventional manner as by a laminated or spiral winder such as is usedin fibre tube and fibre can manufacture. The body ll produced in suchconventional manner is formed of a plurality of ,wall sections or layersI 2 held together by a suitable cement. Such a can body to be suitablefor the purposes described previous to the. performance of the firststep in the present method has been oil and grease proofed in any one ofseveral satisfactory ways by means of which the body wall is madeimpervious to the seepage of oil or grease.

In the practice of the present invention such a can body Il may beinserted on or telescoped over a rotating mandrel l5 (Fig. 3) so thatthe lower end of the body almost or lightly engages an applying rollerl6. Roller I6 preferably rotates with its horizontal shaft (designatedas H) which is arranged above a tank. l8, in which the sealing mixtureindicated by the numeral I 9 is contained. Such an applying roller [6.is rotated in a clockwise direction (as viewed in Fig. 3) and a portionof the mixture l9 from the tank I8 is brought up on the surface of theroller and is deposited inside of the lower edge of the can body II asit rotates with the mandrel l5.

By reason of the rotation of the can body H and the rotation of theapplying roller IS a thin film or stripe of sealing material isdeposited as a strip 20 on the inner wall of the body and also as anedging strip 2|. The seal- Fig. 2 is a perspective view of a metal canend 65 ing mixture IS in the tank I8 is maintained at an elevatedtemperature. preferably at about 225 F. to 240 F. by means of a suitableheating arrangement which may include burners 22 carried on an oilsupply pipe 23. Heating flames 24 maintained by passage of the oil withsuit- 5 able air, through the burners 22, heat the tank sufllciently toraise the temperature of the sealing mixture contained within the tankto the desired temperature.

This sealing mixture is thermoplastic and is in heated condition when itis applied to the can body to form the liner strip 2|. It cools downsumciently to solidify as it builds up the strips 20 and 2|. A suitablemixture may contain the following ingredients:

Per cent Hydrogenated oil 36 Amorphous W 36 Corn l 18 Castor oil 10 20The hydrogenated oil is oil proof and is made by hydrogenating cottonseed, soya bean, peanut oil, castor oil or fish oil. The corn oil may bereplaced by any suitable semi-drying oil such as rape seed oil. Thecastor oil in the mixture is utilized as a plasticizer. The manner ofproducing such a mixture is not of the essence of the present inventionand further description as to this is thought unnecessary.

Following the application of the lining strip 2| to the inner edge ofthe can body II this end of the can body is assembled with a can end.Fig. 2 illustrates a suitable metal can end which is formed with theusual seaming flange 26, th outermost edge of the flange beingpreferably bent back in a hemmed curl 21 (see also Fig. 6). Inassembling can body and end, the former may be inserted in the groove ofthe flange 23 of the end as illustrated in Fig. 4.

The assembled partsv are then subjected to a crimping operation by means.of which the hemmed edge of the flange is bent inwardly against thebody wall. This bending or crimping action may be performed by asuitable crimping roller 28 mounted on a; shaft 29, the can end at suchtime being properly held on a chuck 3| mounted on a shaft 32. Thisbending of the can end flange is a crimping opera-' tion and forciblysqueezes the end of the can body I: within the can end, as illustratedin Fig. 6. In this sealed condition the sealing strips 20 and 2| areconfined between the adjacent sections of the can end and the fibrebody.

After the can end has been crimped in position on the can body, theassembled body and end are subjected to a further treatment as by beingplaced on a hot. plate 35 (Fig. 5) Such a plate is maintained in heatedcondition as by a gas burner 36, by means of which the plate ismaintained preferably at a temperature of substantially 300 F. Thistemperature is sufilciently high to again reduce the thermoplastic vsealing mixture in the strips 20 and 2| to fluid condition. At this timethe mixture flows downwardly between the body and end walls, filling inall of the spaces and effecting a tight end seal or joint 31 (Fig. 6)for the can. A small fillet 33 of the sealing material forms at theinner junction between the body wall and the upper 70 enclosed part ofthe can end. This is additional insurance against any penetration intothe seam of oil or grease contents which may be'subsequently packed inthe can.

It is thought that the invention and many of 7s its attendant advantageswill be understood from the foregoing description, and it will beapparent that various changes may be made in the steps of the processdescribed and their order of accomplishment without departing from thespirit and scope of the invention or sacrificing all of its materialadvantages, the process hereinbefore described being merely a preferredembodiment thereof.

I claim:

1. The method of forming an oil and grease leakproof end seam between acan body and a can end of a fibrous container suitable for lard,vegetable and mineral oils and the like, which comprises applying an oiland grease proofing thermoplastic sealing mixture to the inner wallofthe can body adjacent its end edge, inserting such body end edge intothe flange of the can end, bending the can end edges so as to clamp thesame over the end of said body to produce an end joint within which saidapplied sealing mixture is confined, as a plastic mass in the spacebetween the inner wall of the can body and the adjacent can end wall andbetween the end edge of the can body and the adjacent can end wallandheatingthe said joint to produce liqueficationof the confinedthermoplastic .sealing mixture whereby the'same flows into and fullyfills all spaces between the can body and the can end which are includedin said end joint.

2. The method of forming an oil and grease leakproof end seam between afibrous can body and a metal end of a container suitable for lard,vegetable and mineral oils and the like, which comprises applying aheated, liquefied oil and grease proofing thermoplastic sealing mixtureto the inner wall of the fibrous can body adjacent its end edge so thatsuch mixture solidifies on the body interior wall, inserting the bodyend edge into the flange of the metallic can end, bending the can endedges so as to tightly squeeze the same over the end of said body toproduce an end joint within which said solidified sealing mixture isconfined, as a plastic mass in the space between the inner wall of thecan body and the adjacent can end walland between the end edge of thecan body and the adjacent can end wall and heating the said joint toproduce liquefication of the confined thermoplastic sealing mixturewhereby the same flows into and fully fills all spaces between the canbody and the can end which are included in said end joint.

3. The method of forming an oil and grease leakproof end seam between afibrous can body and a metal can end of a container suitable for lard,vegetable and mineral oils and the like,

which comprises applying a heated oil and grease proofing thermoplasticsealing mixture while in liquid form to the inner wall of the fibrouscan body adjacent its end edge, said sealing mixture which sets oncooling consisting of hydrogenated oils and amorphous waxes and asemi-drying oil, assembling said can body and its can end by disposingthe said body end edge with its solidified sealing mixture within theperipheral flange of the can end, spinning the edge of the can endflange into tight engagement with the said can body wall so that thesaid sealing mixture on the body is confined inside of the spun edge ofsaid can end in a formed end joint, and heating said joint to softensaid confined thermoplastic mixture whereby the same flows into andfully fills all spaces in the joint between the can body and the can endthereby producing a leak-proof seam. 4. The method of forming an oil andgrease leat-proof-end seam between a flbrouscan body I Iointinzwhiclrsaidj ravngedge and a portand a can end closure'oia containersuitable for lard, vegetable and mineral oils and the, like, whichcomprises applying a stripe of thermoplastic sealing material while inliquid form to the inner wall of said body adjacent an end thereof whilesimultaneously applying another stripe of said thermoplastic sealingmaterial in liquid form to the raw edge of said body and contiguous tosaid inner wall stripe, permitting said stripes on said bodyto'solidify, inserting said body end into a flange of said end closure,bending the closure edges so as to clamp the same over and inwardly tionof said inner wallgstripe are 'conflned; 'and.f r

heatingthe said formedj 'e'ndi joint to produce li;

queflcation of the thermoplastic sealing-material whereby the same flowsinto'the-spacesbetween the can body and the closure which are includedin said end joint, the portion of said inner Wall;v stripe not includedin said joint as a result of said bending and heating operations forminga protecting fillet to prevent penetration of the container contentsinto the end joint so formed.

RICHARD P. BIGGER.

